GFAP and lymphoma: To determine the neural cell types that express the Pcdh19 combinatorial code, we used expression markers to identifyexcitatory neurons (B-cell lymphoma/leukemia11B (Bcl11b/Ctip2), Calmodulin 2 (Calm2) and Glutamate Ionotropic Receptor AMPA TypeSubunit 2 (Gria2)), interneurons (Somatostatin(Sst) and Parvalbumin (Pvalb)) and astrocytes (Aquaporin 4 (Aqp4) and Glial fibrillary acidic protein (Gfap)) (figure 2 andelectronic supplementary material, figure S1b).